04. MEMORY - Its basic components, types

• What type of memory loss is most
common during the initial stage of
Alzheimer’s disease?
• A. Short term memory loss
• B. Semantic memory loss
• C. Episodic memory loss
• D. Procedural memory loss

• Ans: A) Short term memory loss

• The simplest way to maintain information
in short-term memory is to repeat the
information in a process called
• a. Chunking.
b. Rehearsal.
c. Revision.
d. Recall.

Long term memory is processed in:
• a) Hypothalamus
• b) Thalamus
• c) Amygdale
• d) Hippocampus
• e) Parietal Lobe

Memory
Memory is the most extraordinary
phenomenon in the natural world. Our
sensory experiences, perceptions and
actions change us continuously and
determine what we are later able to
percivebrains are modified and reorganized
by our experiences.

Our interactions with the physical world, our
sensory experience, our perceptions, our
actions, change us continuously and
determine what we are later able to
perceive, remember, understand, and
become.

The most amazing aspect of human
memory, is the characteristic that it stores
events as video recordings, along with the
associated emotions and feelings.

A subsequent recall therefore also includes,
the reliving of the associated emotions. It is
this phenomena that makes our memories
pleasant and unpleasant.

Higher mental functions such as speech,
thinking, perceptions, moods, psychomotor
skills and consciousness of surroundings are
based is based on memory. Indeed, without
memory there can be no mind..

a. Stages of Memory
Human memory resembles a computer in
that it consists of an information processing
system that has three separate stages:

Encoding :
Sensory information is received and coded
or transformed into neural impulses that can
be processed further or stored for later use.
Just as computer changes keyboard entries
into usable electronic symbols that can be
stored on a disk, sensory information is
transduced, so that it can be used and stored
by the brain.

Apart from transduction a great deal of
encoding process appears to be devoted to
rehearsing or repeating the input.

ii. Storage:
Like a computer program, the encoded
information must be stored in the memory
system. Although some bits of information
are stored briefly or used only once, and
then discarded, others, like certain
telephone numbers, are used frequently, and
are therefore stored on a more permanent
basis.

iii. Retrieval:
Once a computer program has been named
and stored, we can call it up by its name and
use it again. Human memory works in
much the same way. When we recall or
bring a memory into consciousness, we
have retrieved it. This recall process is
known as memory retrieval.

b. Types of Memory:
i. Sensory Memory:
Sensory memory is a memory or storage of
sensory events such as sight, sounds and
taste with no further processing or
interpretation. Sensory memory provides us
with a very brief image of all the stimuli
that present at a particular moment and
therefore has the potential to be quiet large.

Because many are received all the time,
sensory memory appears to last only briefly,
about one half to one second, depending on
which sensory system is involved.

For instance if you see an object, an image
persists for about one-half second
afterwards. Similarly information you hear
is held as a brief echo is sensory memory
for up to two seconds.

ii. Short-term Memory (STM) :
Not everything seen or heard is kept is memory.
Let’s say a TV commercial is running in the
background as your friend reads you notes on
pharmacology. Do you remember the words of the
TV ad? Probably not, because selective attention
determines what information moves on to short-
term memory. Short term memories are also brief,
but longer than sensory memories.

Attending to your friend’s narration will
place his technical jargon in your short-term
memory ( while allowing you to ignore the
voice on TV saying “ talk shawk” ).

Short-term memories can be stored as
images, but more often they are stored as
sounds, especially in recalling words and
letters. Short-term memory acts as a
temporary storehouse for small amount of
information.

Unless the information is important, it is
quickly dumped from STM and is lost
forever. Short-term memory prevents our
minds from collecting useless names, dates,
telephone numbers and other trivia.

At the same time it provides a working
memory where we do much of our thinking,
dialing a phone number, doing mental
arithmetic and remembering a shopping list.

iii. Long-term Memory (LTM):
Information that is meaningful and important is
transferred to the third memory system called
long-term memory. In contrast to STM, long-term
memory (LTM) acts as permanent storehouse for
information. LTM contains everything you know
about the world and yet there appears to be no
danger of running out of room LTM, which is
considered to have a limitless storage capacity.

Information in the LTM is stored on the basis of
meaning and importance and not by sound or
images. When new information enters STM, it is
related to knowledge stored in LTM . This gives
the new information meaning and makes it easier
to store it in LTM.

It is therefore important to built new
information on what you already know
( stored in your LTM) areas of the brain are
responsible for memory, but the
hippocampus is of particular importance.

Recent research in human memory has
revealed that there is more than one type of
LTM. The type of information being
processed influence the nature of the stored
memory.

Three major categories of LTM have been
proposed s illustrated in the following table:

Sensory
Memory
Selective
Attention
Short-Term
Memory
Successfully
Coded for
storage in LTM
Long
Term
Memory
Not
Attended
to
Not
Coded
While
In
STM
Forgotten Forgotten
Incoming
information

Memory is thought to involve at least three
steps. Incoming information is first held for a
second or two by sensory memory.
Information selected by attention is then
transferred to short term memory. If new
information is not rapidly encoded, or
rehearsed, it is forgotten. If it is transferred to
long term memory, it becomes relatively
permanent, although retrieving it may be a
problem.

Type Description Examples
Implicit/
Procedural
Memories used in
making response and
skilled actions.
Remembering how to
dissect, pass a nasogastric
tube, play tennis or drive a
car.
Semantic Our store of general
and specific
knowledge
Water boils at 100 C,
Pakistan is in Asia, and
heart is on the left, motor
cortex is in the medial
frontal lobe
Episodic Memories of personal
events.
Your first day in college,
birth, your patient’s clinical
state

iv. Rehearsal
The process of rehearsal consists of keeping
items of information in the centre of
attention, by repeating them silently or
aloud. The amount of rehearsal given to
items is important in the transfer of
information from short term memory to
long term memory.

Experiments have indicated that the sheer amount
of rehearsal may be less important than the ways
in which information is rehearsed. Just going over
and over what is to remembered (maintenance
rehearsal) does not necessarily succeed in
transferring it to long term memory. What really
works is elaborative rehearsal which is an active
process involving giving the material organization
and meaning as it is being rehearsed.

Forgetting:
Forgetting is the apparent loss of
information already encoded and stored in
long term memory. This means that much
of what we think as forgotten in not really
forgotten because it was never encoded and
stored in the first place.

This usually because some information, due
to lack of attention, may not have reached
short term memory form the sensory
register or due inadequate encoding and
rehearsal, the information may not have
been transferred from the short term
memory to the long term memory. How
much of the information is forgotten
depends on the following factors.

Interference:
Experimental evidence as well as everyday
experience indicates that learning new
things interferes with our memories of what
we learned earlier and prior learning
interferes with memory of things learned
later.

Retrieval problems:
Finding information in the organization
long term memory store is aided by
retrieval cues, or reminders which direct the
memory search to the appropriate part of
the long term memory library. Without the
retrieval cues, the sought for item stored in
LTM may not be found and one forgets.

While we often cannot recall something
while actively searching for it, we may later
recall the sought for information, when we
have given up the search and doing
something else. The new activity in which
we are engaged gives us another set of
appropriate reminders or retrieval cues.

And perhaps the new situation leads us to
search through portions of our LTM store
not examined before. It is therefore a good
idea to ask the examiner to go the next
question in viva vocem, rather than
continuing to retrieve an answer. It will
come to you in a while, when you are
answering another question.

Motivated forgetting:
The theory of motivated forgetting was introduced
by Sigmund Freud when he described a key
concept of psychoanalysis viz. repression.
Repression refers to the tendency of people to
have difficulty in retrieving anxiety provoking or
threatening information. This helps to explain why
people generally remember pleasant events more
often than they do unpleasant ones; the
unpleasant memories have been repressed.

This aspect should encourage to make one’s
learning ‘a lot of fun’, enjoying your studies
and clinical work rather than making it
painful and a burden. This will happen if
you will leave your exam preparation to the
few days try to the exams only.

c. The Anatomy and Biochemistry
of Memory:
The study of organic memory disorders has
led researchers to identify brain that appear
to mediate short term and long term
memory processes. Two of the sky parts of
the limbic system, the hippocampus and the
amygdala embedded under the temporal
lobes are essential in receiving new
information and storing it.

The diencephalons also contains a number of
structures, the most important for memory being
the mammillary bodies, thalamus and
hypothalamus. Lesions to these structures
generally result in problems with encoding of new
information. Although no-one has yet found the
exact physical change in a call that accounts for
memory, many new discoveries have been made
about the physiological basis of learning and
memory.

One of these findings is the role that long
term potentiation (LTP) may play in
memory formation. Studies reveal that
repeated electrical stimulation of nerve cells
in the brain can lead to a significant
increase in the likelihood that a cell will
respond strongly to a future stimulation.

This effect can last for a long time and may be a
key mechanism in the formation of memories.
Studies also indicate that a specific type of
receptor viz. NMDA receptor is extremely active
in long term potentiation as is the role of calcium.
An important part of memory formation is an
increase in the sensitivity of certain nerve cells to
acetylcholine. All these changes suggest that.

d. Methods to improve memory:
In the beginning of the section clearly
indicates that some individuals have
specific techniques through which they
facilitate there memory and learning of new
information. Some of these are as follows:

Knowledge of results:
Learning occurs most effectively when
feedback or knowledge of results allows
you to check and see if you are learning.
Feedback also helps you identify material
that needs extra practice, and it can be
rewarding to know that you have answered
or remembered correctly.

Attention :
A setting that enhance your focus while
studying, and ensures minimal distraction
will turn your attention to the memory job
at hand.

Recitation and rehearsal:
This means repeating to yourself what you
have learned. If you are going re remember
something, eventually you will have to
retrieve it. Recitation forces you to practice
retrieving information as you are learning.

When you are reading a textbook, you
should stop frequently and try to remember
what you have just read by summarizing it
aloud. Your room mate who is sometimes
seen talking to himself, while studying, may
not be “crazy, he may instead be rehearing
what he has just read.

Organize:
Assume that you must memorize the
following list if words; north, man, red
spring, woman, east, autumn, yellow,
summer, boy, blue west, winter, girl, green,
south. The rather difficult list could be
organized into chunks as follow; north-east-
south-west, spring –summer-autumn-boy-
girl.

Similarly by making up stories using long
list of words to be memorized makes
remembering the list much easier.

Selection:
The Dutch scholar Erasmus said that a good
memory is like a fisherman’s net. It should
keep all the big fish and let the little ones
escape. If you boil down the paragraphs in
your textbooks to one or two important
terms or ideas, you will find memorizing
more manageable.

Practice careful and selective marking in
your textbooks and marginal notes to
further summarize ideas. Most students
mark their texts too much instead of too
little. If everything is underlined, you
haven’t been selective.

Serial position:
Whenever you must learn something, be aware of
the serial position effect. This is the tendency to
make most errors is remembering the middle of a
list. If you are introduced to a long line of people,
the names you likely to forget will be those in the
middle, so you should make an extra effort to
attend to them. The middle of a list, poem or
speech should therefore be given special attention
and extra practice.

Mnemonics:
A mnemonic is any kind of memory system or aid.
People demonstrating extraordinary feats with
their memories are actually using mnemonics to
perform this. Mnemonic techniques rely on the
linking or association of to-be-remembered
material with a systematic and organized set of
images or words that are already firmly
established in long term memory and can therefore
serve as retrieval cues.

An example of this happens when we are
trying to remember how many days there
are in a month and recite “ Thirty day halt
September…” Similarly medical students
often invent mnemonics for memorizing the
names of cranial nerves; amino acids etc
and can remember these lists for lengthy
periods.

The basic principles in the formation of
mnemonics are :
• Use mental pictures
• Make things meaningful
• Make information familiar
• Form bizarre, unusual or exaggerated
mental associations.

Attach emotions, feelings:
Or link up with an event, We hardly ever
forget what is emotionally significant in our
lives. Senior citizens continue to recall
events of emotional significance even when
their short term memory is grossly impaired

Using Mental Pictures or Visual
Imagery
• Using mental pictures or visual imagery to
enhance retention. One way is to simply
imagine an unusual scene that includes the
various elements you want to remember. F

• For intance in your way home, you have to
shop for a newspaper, notebook, pen and
shaving cream. To remember this list of
items, you have to make up a mental image
of something funny and bizarre such as you.

• Opening up the front page of a newspaper
to find a picture of a person reading a
notebook with one hand and using a pen to
wipe off the shaving cream on his face with
the other hand.

Over learning:
Many studies indicate that memory is
greatly improved when study is continued
beyond bare mastery. In other words after
you have learned material well enough to
remember it without error, you should
continue to study the material. Over
learning is your best insurance against
going blank on a test because of anxiety.

Spaced practice:
Spaced practice generally is superior to
massed practice. By improving
concentration, three 20 minutes study
sessions can produce more learning than
one hour of continuous study.

Whole versus part learning:
Generally it is better to practice learning
whole packages of information rather than
smaller parts. Try to study the largest
meaningful amount of information possible
at one time. This means, reading a textbook
is better than reading condensed notes. The
only notes that will benefit you will be the
ones that you make yourself based on steps
listed above.

Sleep:
Sleeping after study is helpful and reduces
the interference. Similarly breaks and free
times in a schedule are as important as the
study periods. Staying awake the whole
night before your exams is after all not the
smart thing to do.

Review:
Reviewing shortly before an examination is
helpful, though one should avoid the
tendency to memorize new information at
that point. This review should however over
an hour or so rather than spending the
whole night prior to the exam.

e. Pathological Changes in
Memory
Before considering the pathological basis of
memory loss, it is important to run simple
tests of a person’s cognitive functions such
as attention, concentration, registration and
motivation. In case of an impairment of one
or more of these higher mental functions,
the function of memory does not come into
play.

Pathological Changes in Memory

People with low mood, poor motivation and
consequent lack of attention and
concentration my therefore complain of “
loss of memory “ this state is called
pseuododementia.

Another situation, in which people
sometimes experience a significant
alteration in their memory or identity, occur
on account of loss of integrative function of
the brain due to an emotional challenge or a
stress that could be social, psychological or
structural.

Such stress can interrupt in learning new
information or recalling old information, or
by changes in the ability to think and
process information, result in disruption of
memory and identity.

These alterations in memory ( and or of
identify, or consciousness) sometimes lack
a clear physical cause and are called
dissociative disorders. The principal
symptom in such situations in an inability to
recall important personal events and
information of personal significance.

Disturbances in memory and identity that
have clear physical cause include amnestic
disorders and dementias. Amnestic
disorders affect a person’s memory
exclusively, either for events before an
amnesia inducing trauma or for information
learned after it or both.

They are caused by medical conditions,
such as thiamine deficiency,
hypothyroidism, hypoglycemia, chronic
alcohol or substance abuse, head injury or
other problems that can adversely effect the
physical functioning of the brain.

Dementias involve more then just memory
and are characterized by deficits in other
areas of cognitive functioning as well such
as reasoning and problem solving. They are
caused primarily by degeneration disease
that affect specific area of the brain. The
most common amongst them is Alzheimer’s
disease.

Q. The Anatomy of memory is
mainly linked to :
• a) Cerecaral Cortex
• b) Basal Ganglia
• c) Cerebellum
• d) Mammilary Bodies
• e) Substantia Nigra

Q. Which of the following can lighten
the load on memory and enhances our
ability to communicate in the best way?
• a) Problem solving
• b) Making Decision
• c) Concepts
• d) Creative thinking
• e) Emotions

04. MEMORY - Its basic components, types

04. MEMORY - Its basic components, types

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04. MEMORY - Its basic components, types